netdev - Re: libpcap and tc filters

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Date:	Mon, 04 Jul 2011 10:06:56 -0400
From:	jamal <hadi@...erus.ca>
To:	Adam Katz <adamkatz0@...il.com>
Cc:	netdev@...r.kernel.org
Subject: Re: libpcap and tc filters

On Mon, 2011-07-04 at 16:24 +0300, Adam Katz wrote:
> ok, I checked now and the packets sent by tcpreplay are identical to
> the ones captured originally by wireshark.

Ok - thanks for removing that variable.

> I'm using the stock ubuntu 10.04 kernel that wasn't compiled with
> CONFIG_CLS_U32_PERF so sudo tc -s filter ls dev eth1 shows nothing
> useful (and i'm not sure that recompiling the entire kernel is worth
> it to tell me what I already know - that these packets missed the
> filters... but i'm willing to do it if you think that'll help).

Not necessary as long as you can tell where the packets end up.

> Anyway, I suspect the problem to be something else - I suspect that
> the packets sent using tcpreplay simply skip the filters in the kernel
> and are being injected somewhere afterwards. But this theory is
> problematic since I find it strange that the packets do end up in the
> default queue after all - hence they ARE seen by tc and they don't
> skip tc entirely.

I am not sure off top of my head why that would happen. I will try later
to install tcpreplay and reproduce your test.

cheers,
jamal

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